LA GRANDE, Ore. -- Nine people were killed and at least 20 others hospitalized on Sunday after a tour bus veered out of control on an icy stretch of freeway in eastern Oregon and rolled nearly 200 feet down an embankment, state police said.

State police reported that the driver apparently lost control of the charter bus around 10:30 a.m. on the snow- and ice-covered lanes of Interstate 84 and crashed through a guardrail before plunging down an embankment. The Oregonian newspaper reported that the bus tumbled nearly 200 feet before coming to a halt.

Oregon State Police Lt. Gregg Hastings told the newspaper that about 40 passengers were on the bus at the time of the crash, which occurred near milepost 227 on Interstate 84 near Deadman Pass, according to the East Oregonian newspaper.

Hastings told the East Oregonian that he learned the bus was returning to Las Vegas from British Columbia, Canada.

Rescue workers used ropes to help retrieve the injured from the scene. Westbound lanes of I-84 were closed.

The Oregonian said 18 passengers were transported to St. Anthony's Hospital in Pendleton, about 13 miles northwest of the crash scene. Hospital spokesman Larry Blanc would not say if or how many passengers sustained life-threatening injuries, it said.

Three fixed-wing aircraft also were on standby at the Pendleton airport if needed to transport injured to hospitals elsewhere, state police said.

Authorities did not immediately identify the operator of the charter bus.

Oregon State Police / Reuters

Rescue personnel respond to the scene of a charter bus crash on I-84, east of Pendleton, Ore. in this photo released on Dec. 30. Police said the bus may have gone out of control on the highway before crashing through a guardrail and down an embankment.